This is the 1413th most frequent Russian word.
героями
"Героями" means "heroes" (instrumental plural form).
The word 'героями' is used in an instrumental plural form, referring to plural heroes as associated instruments of the action.
Дети читали книги о великих героями истории.
The children read books about the great heroes of history.
Here 'героями' is the instrumental plural form, highlighting the state of becoming heroes.
Мы впечатлены подвигами наших соотечественников, ставших героями.
We are impressed by the deeds of our compatriots who became heroes.
In this sentence, 'героями' functions as the instrumental plural form, referring to heroes as the agents providing inspiration.